Condensed Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury stock, at cost
Beginning Balance (in shares) at Jul. 31, 2017		41,728,934
Beginning Balance at Jul. 31, 2017	$ 523,932	$ 4,619	$ 174,602	$ 407,590	$ (9,900)	$ (52,979)
Increase (Decrease) in Stockholders' Equity
Repurchases of shares (in shares)		(52,008)
Repurchases of shares	(5,822)					(5,822)
Stock-based compensation	1,851		1,851
Equity vestings/option exercises (in shares)		42,168
Equity vestings/option exercises	879	$ 5	874
Cancellations of restricted stock (in shares)		(1,315)
Cancellations of restricted stock	0
Dividends on common stock	0			0
Net income	22,929			22,929
Other (in shares)		88,100
Other	42	$ 10	32
Other comprehensive income (loss)	(1,233)				(1,233)
Ending Balance (in shares) at Oct. 31, 2017		41,805,879
Ending Balance at Oct. 31, 2017	542,578	$ 4,634	177,359	430,519	(11,133)	(58,801)
Beginning Balance (in shares) at Jul. 31, 2017		41,728,934
Beginning Balance at Jul. 31, 2017	523,932	$ 4,619	174,602	407,590	(9,900)	(52,979)
Increase (Decrease) in Stockholders' Equity
Net income	74,153
Other comprehensive income (loss)	4,608
Ending Balance (in shares) at Apr. 30, 2018		41,709,335
Ending Balance at Apr. 30, 2018	601,306	$ 4,046	183,551	478,197	(5,292)	(59,196)
Beginning Balance (in shares) at Oct. 31, 2017		41,805,879
Beginning Balance at Oct. 31, 2017	542,578	$ 4,634	177,359	430,519	(11,133)	(58,801)
Increase (Decrease) in Stockholders' Equity
Repurchases of shares (in shares)		(1,272)
Repurchases of shares	(131)					(131)
Stock-based compensation	2,739		2,739
Equity vestings/option exercises (in shares)		0
Equity vestings/option exercises	0	$ 0	0
Cancellations of restricted stock (in shares)		(1,604)
Cancellations of restricted stock	0
Dividends on common stock	(3,545)			(3,545)
Net income	32,488			32,488
Other (in shares)		(88,100)
Other	(25)	$ (10)	(15)
Other comprehensive income (loss)	12,379				12,379
Ending Balance (in shares) at Jan. 31, 2018		41,714,903
Ending Balance at Jan. 31, 2018	586,483	$ 4,624	180,083	459,462	1,246	(58,932)
Increase (Decrease) in Stockholders' Equity
Repurchases of shares (in shares)		(2,336)
Repurchases of shares	(264)					(264)
Stock-based compensation	2,443		2,443
Equity vestings/option exercises (in shares)		620
Equity vestings/option exercises	0	$ 0	0
Cancellations of restricted stock (in shares)		(3,482)
Cancellations of restricted stock	0
Net income	18,736			18,736
Other (in shares)		(370)
Other	446	$ (578)	1,025	(1)
Other comprehensive income (loss)	(6,538)				(6,538)
Ending Balance (in shares) at Apr. 30, 2018		41,709,335
Ending Balance at Apr. 30, 2018	$ 601,306	$ 4,046	183,551	478,197	(5,292)	(59,196)
Beginning Balance (in shares) at Jul. 31, 2018	41,706,084	41,706,084
Beginning Balance at Jul. 31, 2018	$ 608,867	$ 4,624	184,212	491,540	(11,456)	(60,053)
Increase (Decrease) in Stockholders' Equity
Repurchases of shares (in shares)		(37,802)
Repurchases of shares	(4,288)					(4,288)
Stock-based compensation	2,576		2,576
Equity vestings/option exercises (in shares)		53,320
Equity vestings/option exercises	955	$ 7	948
Cancellations of restricted stock (in shares)		(286)
Cancellations of restricted stock	0
Dividends on common stock	0			0
Net income	19,242			19,242
Other	(634)		(634)
Other comprehensive income (loss)	(5,223)				(5,223)
Ending Balance (in shares) at Oct. 31, 2018		41,721,316
Ending Balance at Oct. 31, 2018	$ 622,360	$ 4,631	187,102	511,647	(16,679)	(64,341)
Beginning Balance (in shares) at Jul. 31, 2018	41,706,084	41,706,084
Beginning Balance at Jul. 31, 2018	$ 608,867	$ 4,624	184,212	491,540	(11,456)	(60,053)
Increase (Decrease) in Stockholders' Equity
Equity vestings/option exercises (in shares)	30,000
Net income	$ 46,217
Other comprehensive income (loss)	$ (8,199)
Ending Balance (in shares) at Apr. 30, 2019	41,765,917	41,765,917
Ending Balance at Apr. 30, 2019	$ 655,865	$ 4,636	201,116	534,449	(19,655)	(64,681)
Beginning Balance (in shares) at Oct. 31, 2018		41,721,316
Beginning Balance at Oct. 31, 2018	622,360	$ 4,631	187,102	511,647	(16,679)	(64,341)
Increase (Decrease) in Stockholders' Equity
Repurchases of shares (in shares)		(880)
Repurchases of shares	(67)					(67)
Stock-based compensation	3,587		3,587
Equity vestings/option exercises (in shares)		1,857
Equity vestings/option exercises	0	$ 0	0
Cancellations of restricted stock (in shares)		(1,107)
Cancellations of restricted stock	0
Dividends on common stock	(4,173)			(4,173)
Net income	18,800			18,800
Other	1,513		1,513
Other comprehensive income (loss)	(417)				(417)
Ending Balance (in shares) at Jan. 31, 2019		41,721,186
Ending Balance at Jan. 31, 2019	641,603	$ 4,631	192,202	526,274	(17,096)	(64,408)
Increase (Decrease) in Stockholders' Equity
Issuance of shares (in shares)		42,705
Issuance of shares	3,197	$ 4	3,193
Repurchases of shares (in shares)		(3,712)
Repurchases of shares	(273)					(273)
Stock-based compensation	5,722		5,722
Equity vestings/option exercises (in shares)		5,875
Equity vestings/option exercises	0	$ 1	(1)
Cancellations of restricted stock (in shares)		(137)
Cancellations of restricted stock	0
Dividends on common stock	0			0
Net income	8,175			8,175
Other comprehensive income (loss)	$ (2,559)				(2,559)
Ending Balance (in shares) at Apr. 30, 2019	41,765,917	41,765,917
Ending Balance at Apr. 30, 2019	$ 655,865	$ 4,636	$ 201,116	$ 534,449	$ (19,655)	$ (64,681)